1. Field of the Invention
The present invention relates to a continuously variable valve lift actuator of an engine, and more particularly to a continuously variable valve lift actuator of an engine to control a lift amount of a valve according to operational conditions of a vehicle.
2. Description of the Related Art
A valve device applied to an engine of a vehicle supplies a mixed gas into a combustion chamber and exhausts a combustion gas according to strokes of the engine.
Recently, variable valve devices, which optimize an inflow amount of the mixed gas and an exhaust efficiency of the combustion gas by changing an open degree and an opening/closing time of a valve according to operational conditions, that is, an operational region of the engine divided by revolutions per minute (hereinafter, referred to as ‘RPM’) and a load of the engine, have been developed and applied to the engine.
Accordingly, the variable valve device of an engine for a vehicle may improve a performance of the engine such as fuel efficiency, a torque, and an output of the engine and reduce an amount of an exhaust gas.
The variable valve device of an engine for a vehicle includes a variable valve timing unit to change an opening/closing time of a valve, a variable valve lift unit to change an open degree of the valve, and a variable valve actuation angle unit to change an actuation angle of the valve.
Among the above units, the variable valve timing unit improves an output and a fuel efficiency in a middle/low speed mode, and is divided into a rocker arm type, a pivot type, a tappet type, and a bucket type.
The applicant of the present invention has filed a technology regarding a variable valve lift device as Korean Patent No. 10-1084739 issued on Nov. 22, 2011, Korean Patent No. 10-1084741 issued on Nov. 22, 2011, and Korean Unexamined Patent Publication No. 10-2012-0088363 published on Aug. 8, 2012.
However, when the continuously variable valve lift actuator according to the related art is applied to a vehicle, pumping loss is increased because a throttle body sucks air upon an intake stroke.
Therefore, there is a need for development of a technology capable of reducing the pumping loss by controlling a suction amount of air by an intake valve of an input port of a cylinder by improving a structure of the continuously variable valve lift actuator applied to a gasoline engine.
Further, there is a demand for development a technology to improve a fuel efficiency and an output of a vehicle by controlling an intake amount of air in an operation state, that is, a high speed operation state or a low speed operation state of the vehicle.
In addition, the continuously variable valve lift actuator of an engine according to the related art needs a process of controlling valve clearance in a state that the continuously variable valve lift actuator is mounted in the engine.
In this manner, according to the related art, since the control operation is performed in a state that the continuously variable valve lift actuator is mounted in the engine, if the control of the valve clearance fails, it is necessary to perform the control operation by replacing the continuously variable valve lift actuator with new one after separating the continuously variable valve lift actuator from the engine.
Accordingly, productivity of the engine and the quality of a product are degraded when using the continuously variable valve lift actuator of the engine according to the related art.